Sewage shredder



Dec. 27, 1938. s, F, 055mg 2,141,663

SEWAGE SHREDDER Filed Dec. 28, 1936 3 Sheets-Sheet 2 l I [NVENTOR' E,;q 4 7 STANLEY E Ossmcs De Z7,1938.' s.F.oss'lN G 6 SEWAGE SHREDDER I Filed Dec. 28, 1936 1 3 Sheets-Sheet 5 s t a f/YVE/VTOR.

STANLEY F. OSSING, BY

- ATTX Patented Dec. 27 1938 SEWAGE SHREDDEB Stanley F. Ossing, Columbus, Ohio, assignor to The Jeffrey Manufacturing Company, a corporatlon of Ohio Application December 28, 1936, Serial No. 117,844

8 Claims.

This invention relates to a sewage shredder v and is particularly adapted to reduce sewage or similar material, such as garbage, which may include an appreciable amount of fibrous material,

, such as rags, which are very diflicult to reduce or shred and which tend to clog the ordinary shredder or grinder.

An object of the invention is to provide a device of the above mentioned class in which the reducing operation is veryemciently performed on sewage or garbage containing fibrous material.

Another object of the invention is to provide a built up rotor in which a plurality of stacked discs are employed which carry rempvable teeth.

Still another object of the invention is to provide a rotor which may be formed bya minimum number of discs to provide a maximum number of transverse rows of teeth.

Still another object of the invention is to provide an improved rotor construction for a shredder.

Another object of the invention is to provide an improved disc for a shredder rotor.

A further object of the invention is to provide a shredder rotor having a plurality of triangular teeth which may be adjusted in any one of a plurality of positions to bring into operation any one of a plurality of cutting edges.

Still another object 'of the invention is to'provide an improved tooth for a sewage shredder.

Other objects of the invention will appear hereinafter, the novel features and'combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is a side elevational view of the shredder comprising my invention;

Fig. 2 is a rear elevational view of the device of Fig. 1;

Fig. 3 is a longitudinal sectional elevational view of the device of Figs. 1 and 2;

Fig. 4 is an elevational view of the shredder rotor showing its relation to the shredder grating;

Fig. 5 is a plan development of the peripheral surface of the rotor;

Fig. 6 is a side elevational view of the rotor with the shaft shown in section; V

Fig. '7 is a side elevational view of one of the raking discs of the rotor;

Fig. 8 is a side elevational view of one of the hammer discs of the rotor;

Fig. 9 is a plan view of the lower portion of the shredder showing particularly the base casting and the grating thereof; and

Fig. 10 is a perspective view of one of the shredder teeth.

The shredder comprising my invention comprises a, casing or housing formed by a base casting 2i providedwith a pair of side arcuate flanges 22 which support a combination screenand grating 23 formed by a pair of similar arcuate grating sections 24, 24. Each of said grating sections 24, 24 comprises a plurality of arcuate longitudinally extending toothed bars 25 having teeth 26 on their inner arcuate surfaces which have radially extending reducing surfaces providing shredding edges 21. 'As will be hereinafter described in full detail, the teeth 26 cooperate with the rotor of the shredder to reduce the material being treated, such as sewage or garbage. Said bars 25 are rigidly connected together by transverse bars I24 having top shredding edges.

To provide access to the bottom of the grating 23, both forwardly and rearwardly of the shredder, 1' provide a removable rear door 28 and a removable front door 29. Appropriate locking means 30 and 3| are provided for said doors 28 and 29, respectively.

Mountedupon and rigidly attached to the base casting 2! is an upper member 32 held in place by a plurality of nuts and bolts 33, The upper member 32 and the base casting 2| cooperate to provide a reducing chamber 34 within which the hereinafter described rotor is adapted to rotate. Said upper member 32 carries a transversely extending V-shaped partition 35 which cooperates to form a material receiving hopper 36 by which access is provided to the reducing chamber 34 through a top opening, 31. Extending transversely of and adjacent the top of the hopper 35 is a spray pipe 38 adapted to supply waterto the hopper 36 and to the reducing chamber at;

Adjacent its forward and bottom portion the top member 32 forms an opening closed by a cover plate 39. Below the cover plate 39 and adjacent its top, the member 32 carries a transversely extending bar 60 which prevents the materlal from entering the reducing chamber 34 adjacent the forward end of the shredder where it would not be properly reduced and at the same time prevents any material from being thrown upwardly into the hopper 36 or out through the opening 31-. In addition, the bar Ml has a lower shearing edge N0 which cooperates with the rotor, as hereinafter described, to reduce any large particles of material which have improperly ,gained entrance into the forward portion of the reducing chamber. Said cover plate 39 is removably attached to the upper member 32 by appropriate nuts and bolts M and in fact forms a removable part of said upper member 32. Said cover plate 39 also carries a transversely extending casting 42 which rests upon one end of one of the grating sections 24 to hold it down in proper position. To insure a. proper holding down of said grating section 24by the casting 42, bolts 43 pro-' vided with appropriate nuts also rigidly attach said casting 42 to the base casting 2I.

Adjacent its rear end the upper member 32 carries a transversely extending casting 44 forminga stationary preliminary breaker 'plate provided with side flanges 45 by which it is removably attached to said upper member 32, as by appropriate nuts and bolts 46. The casting 44 is provided with an upper curved lip 41 which coperates with the partition 35 to provide a throat 48 leading to a tramp material compartment 49. Access to said tramp material compartment 49 is gained through a removable rear door 59 removably held in place by locking means I".

The casting 44 is also provided with a plurality of teeth 52 having radially extending surfaces providing shearing edges 53 which extend transversely the entire width of the shredder within the reducing chamber 34, which casting 44 is provided with a pair of spaced abutment bosses I44 to space it from door 59. The bottom of said casting 44 rests upon a plurality of transversely extending bars 54, the bottom one of which rests directly. upon the end of the rear grating section 24 and holds it down.

Said bars 54 are provided with a plurality of teeth 55 which are in longitudinal alignment with the teeth 26 of the grating 23, as best seen in Fig. 9 of the drawings. A rear spacer 56 and end spacers 51 (see Fig. 9) are preferably provided to maintain the bars 54 in adjusted position. The ends of the bars 54 rest in appropriate recesses in the sides of the base casting 2| which are closed by removable plates 58.

Adjacent each .side, the base casting 2I is provided with an integral standard 59 carrying a bearing box 69 housing anti-friction bearings for supporting the shaft 6I of the rotor 62. Rotor 62 is adapted to rotate in the'reducing chamber 34 and to reduce material to such a fine state that it will pass through the grating 23 in a manner hereinafter described in full detail.

Attention is now directed to the particular construction of the rotor 62 comprising my invention. Said rotor 62 is formed by two groups'of identical discs which are alternately mounted upon the shaft 6I in a stacked relation, alternate identical discs being positioned 180 degrees apart on said shaft 6|.

Before describing the entire rotor assembly attention is directed to the construction of the discs of said groups. In Fig. 7 there is illustrated a'disc 63 comprising one of the raking discs. In Fig. 8 of the drawings there is illustrated one of the discs 64 comprising one of the hammer discs. The raking discs 63 will all be alike and the hammer discs 64 will all be alike. The discs 63 and 64 will have substantially the samediameter.

Furthermore, each of said discs will be'provided with a pair of keyways spaced 180 degrees apart, seen at 65, 65 in discs 63 and at 66, 66 in disc 64. In addition, each of said discs 63 and64 will be provided with an odd number of V-shaped notches seen at 61 and 68 in discs 63 and 64, respectively. As illustrated in Figs. 7 and 8 of the drawings, there are five of said notches 61 and 68 which are equally spaced about the peripheries of the discs 63 and 64, respectively. This number may be increased or decreased, but it is preferred that it always be an odd number and the notches should be equally spaced about the disc periphery. It isalso preferred that each of said notches 61 and 68 have one edge radial and each form an angle of 60 degrees whereby the inner walls of such notches will form V-shaped seats to receive and contact the edge surfaces of the equilateral triangular shaped teeth 69 or 19 of which the teeth designated 69 are adapted to act as raking teeth and the teeth designated 19 are adapted to act as hammer teeth for reasons hereinafter pointed out in full detail. Each tooth 69 or is provided with three equally spaced shearing edges extending parallel to the axis of the motor.

In Fig. 10 I have illustrated one of the teeth 69. This representation will also apply for a hammer tooth 10 except for the thickness or width thereof. In practice a raking tooth 69 preferably has a width or thickness approximately twice that of a hammer tooth 10; as an example, the former may be one-half inch in thickness and the latter onequarter inch in thickness. Both the raking teeth 69 and the hammer teeth 19 are formed in the shape of equilateral triangles and each has an aperture H at its center, the aperture 1| being seen for a tooth 69 in Fig. 10.

As also seen in Fig. 10, each tooth 69 has nine cutting or shearing edges, three of which are seen at I1I, three at I12 and three at I13. When the device is in operation, the edges "I are parallel with the axis of rotation of rotor 62 and the edges I12 and I13, are perpendicular thereto. Teeth 10 are similarly formed. Edges I1I of teeth 16 cooperate particularly with shearing edges 53 of stationary breaker plate 44, bars 54, bars I24 and edge I40 of bar 49, to effect a shredding action. Edges I12 and I13 cooperate particularly with teeth 55 of bars 54, and with the radial shredding edges 21 of teeth 26 on bars 25 to effect the greater amount of final shredding action. Edges I1I of teeth 69 operate particularly to remove fibrous material which tends to build up on bars 25 and cover the shearing edges 21 thereof, thus insuring that said cutting or shearing edges 21 will be exposed at all times to provide a maximum efficiency of shredding action on the sewage or garbage being reduced.

By a comparison between Figs. 7 and 8 of the drawings, it will be noted that the notches 61 are deeper, or in other words, have a greater radial dimension, than the notches 68. In view of this fact the hammer teeth 19, associated with the discs 64, will project out farther beyond the periphery of the entire rotor 62 than will the raking teeth 69 associated with the discs 63. There is another difference between the discs 63 and 64 in that said discs 63 have a greater thickness than the discs 64. This, of course, is to provide for the accommodation of the difierence in thickness or width of the teeth 69 or 10, and for another important reason hereinafter set forth.

There is still a further difference between the discs 63 and 64. As clearly seen by a comparison of Figs. '7 and 8 of the drawings, with two discs 63 and 64 keyed on a shaft 6I, the notches 68 will be angularly displaced from the notches 61 a predetermined amount. This amount will be a function of the number. of notches 61 and 68 provided in the discs 63 and 64, respectively. In the illustration given, displacement will be 18 degrees, or one-twentieth of a complete circle.

' The displacement desired will be determinedin any case by multiplying the number of notches in any disc by four and dividing the product into 360, since there two diflerent kinds of discs and each kind is alternately reversed.

A As clearly illustrated in Fig. 4 of the drawings, the complete rotor 62 is formed by stacking a plurality of discs 63 and 64 and keying them to the shaft 6|. The discs 63 and 64 are alternately placed upon the shaft 6|. In addition, alternate similar discs are placed on the shaft 6| 180 degrees apart. That is, in a typical illustration, a raking disc 63 will first be placed on the shaft 6| in the position'illustrated in Fig. I. A hammer disc will then be placed on the shaft 6| in the position illustrated in Fig. 8. This will be followed by another raking disc 63 being placed on the shaft 6|, but before being placed on said shaft 6| it will be rotated 180 degrees from the position illustrated in Fig. 7. A similar procedure will be followed in placing the next hammer disc 64 on the shaft 6|. This procedure will be repeated until the entire rotor 62 is built up to a desired axial length.

It is preferred that a raking disc be on each extreme end of the stacked rotor discs excluding, of course, the end discs hereinafter described.

After the discs 63 and 64 have been stacked, as above described, a row of teeth 69 or III will be dropped into a laterally extending aligned row .of notches 61 or 68.

To hold said teeth vide a plurality of transversely extending round rods I2 which project through the aligned apertures of the teeth 69 and I0, such as the apertures II of the teeth 69.- These rods I2 also project through aligned openings I3 or I4 in the discs 63 and 66. Due to the fact that the hammer teeth I0 are positioned to travel in a circle having a greater diameter than that described.

it is evident that the distance of the openings 13 from the axis of the shaft 6| will be greater than the distance of the openings I4 from the axis of said shaft 6|. It will thus be seen that.the rods 12 maintain the teeth 69 and Ill'ln the peripheral notches 61 and -68 formed in the discs 63 and 64, respectively. ln addition, it will be evident that each of the teeth 69 and I6 will be clamped between a pair of adjacent discs 63 or 64 to hold them rigidly in position.

To provide for the maintenance of the rods I2 in tooth locking position and to prevent longitudinal movement thereof in the assembled rotor, yet to provide for the removal of said rod I2 to permit removal of the teeth 69 or 16, which may be desired either to renew said teeth or to rotate them to present a new cutting edge, of which there will, of course, be three, provided by each tooth 69 and I6, I provide a pair of end discs 15 and I6, which are of similar but of reverse by the raking teeth 69,

construction. As said end discs I and I6 are.

similar, a description of the disc I6 will sumce for an understanding of the construction of disc I5. Said disc I6 has a diameter substantially equal to the diameter of the discs 63 and 66. It is provided with a central aperture 1I whereby it may slide over the shaft 6i. Said disc I6 is mounted for free rotation on said shaft 6|. It is provided with a pair of arcuate elongated apertures I8, I8 and a second pair of elongated arcuate apertures I9, I9.

Extending entirely through the series of stacked discs 63, 64, 15 and I6 are a pair of elongated bolts 80, 60 provided with appropriate nuts which, when screwed home, clamp all of said plates rigidly together. A second pair of 69 and I0 in place I proelongated was 0|, 8| provided with appropriate nuts are provided which clamp the discs 63, 64

The elongated slots limited angular rotation of the end discs I6 and- I6 so that in one position of adjustment the rods I2 will abut the discs I6 and 16 and thus be held against longitudinal movement, while in another position of adjustment said rods I2 will be-positioned opposite two series of apertures 62 and 83 which will provide for the ready insertion or removal of said rods I2. That is, the series of apertures 62 will align with the apertures 13, and the series of apertures 83 will align with the apertures I4 in one position of' adjustment of the discs I6 and I6. It will be evident that when this alignment is effected rods I2 may be readily inserted or removed. It is also evident that upon rotation of the plates I5 and I6 so that the apertures I3 and I4 are no longer aligned withthe apertures 82 and 83, respectively, said rods I2 will be held against longitudinal movement.

To provide for the ready turning of the discs I5 and I6 through the limited extent, as above indicated, said discs are provided with appro-.

- in either direction.

Attention is now directed particularly to Fig. 5- I of the drawings which illustrates a preferred arrangement of the teeth. It is to be noted that any row of transversely aligned teeth is formed by teeth of one class, that is, by hammer teeth Ill or by raking teeth 69.

It .is also to be noted that except for the two central hammer teeth of any transverse row, each tooth is spaced transversely from an aligned'tooth by a space equal to the width of three teeth, one of like character and two of unlike character. This is particularlydesirable because it provides an appreciable spacing between the teeth to allow material to drop down into a space where it will be disintegrated. If the teeth are too close together-there will be a tendency for the material to ride on top of the rotor 62 in which case it will not be effectively disintegrated.

The direction of rotation of the rotor may be selected as desired, though said rotor is normally rotated in the direction illustrated by the arrow 85, as seen in Figs. 4 and 5. As seen in Fig. 3 of the drawings, it is essential that the rotor rotate in the direction of the arrow 86.

In the operation of the device comprising my invention, material to be reduced, such as sewage or garbage, which contains fibrous material such as cloth or rags, will be fed to the hopper 36 through the top opening 3i. A liberal amount of Water will be supplied to the hopper 36 and to the reducing chamber 34 by the spray pipe 38. The

I8 and I3 provide for L rotor 62 will be rotated in the direction of the arreduction of the material will take place due to the shredding or grinding action between the edges, III of teeth 69 and I0 and the teeth 52 of the stationary breaker plate 44. Due to the fact thatthe hammer teeth ID are positioned closer to the teeth 52 they will perform the principal reducing operation in this initial stage.

After the material is so reduced it is carried into the bottom of the reducingchamber 34 and acted upon first by the teeth 69 and I0, particularly the shredding edges I12 and "3 thereof, in cooperation with the radial edges of teeth 55 of bars 54, then in cooperation with the radial edges of teeth 26 of the screen and grating 23. In this operation the radial edges 21 of the teeth 26 will, of course, cooperate with the radial edges I12 and I13 of the teeth 69 and ID to effect a thorough shredding and reducing of the material. The principal shredding and reducing will be effected by the hammer teeth III which extend between the teeth 26 of the bars 25. v

The transverse edges III of raking teeth 69 are particularly effective to prevent a building up or accumulation of'material on said bars 25 which, if allowed, would soon effectively cover their sharp shearing or shredding edges and reduce appreciably their shredding action in cooperation with said teeth I0. As a consequence, the grating 23 is maintained clear of accumulated and built up material at all times whereby the sharp edges of the teeth 26 will be most eflectively exposed to perform the shredding operation. 2

It may be noted that the hammer teeth .10 have substantially the same thickness as the grating bars 25 and the raking teeth 59 have substantially the same thickness as the spaces betwensaid bars 25.

Any material which reaches the forward portion of the reducing chamber 34 without being properly reduced will be reduced by the action of the edges III of hammer teeth III in cooperation with the shearing edge I 40 of transverse ban).

After the material is reduced to a very fine state and the fibrous material is cut into short threads, it will pass easily through the screen and grating 23 in a finely reducedstate. It is preferred that this state be of such fineness that the material will readily pass through pumps as it is desired to feed said material to a sewage stream where it will be conveyed for treatment to a sewage dis- DOsal system of the digester type.

It is also to be noted that the water supplied by the pipe 38 will be effective to flush the entire grinder to keep it free of any adhering material and to aid in the grinding operation. In addition, said water will be effective to carry the reduced material through the screen and grating 23 after it is reduced to the desired state of fineness.

Any irreducible material, such as tramp iron, which enters the hopper 36 is deflected toward the left, as seen in Fig. 3, by the upper side of the bar 40 and then thrown by the teeth 69 or 10 into the throat 48 along any one of a number of paths,

' as illustrated by the lines 31, 88. The path illustrated by line 81 leads directly through throat 48 to the tramp material compartment 48; The face 41 of the curved lip 41 preferably has the shape of a segment of a cylinder and is located under the inclined roof of the deflector 35. Asa consequence any material thrown to strike lip 41, as illustrated by the line 38, will be deflected by face 41' to strike the inclined roof of deflector or partition 35 by which it is directed to tramp material compartment 43.

It is to be particularly noted that the tramp material is thrown out of reducing chamber 34 as soon as it enters and does not travel around with rotor 62, even for a single revolution. It is also to be noted that said tramp material compartment 49 is at the rear of the machine, toward which tramp material is thrown directly from the rotor 62. This results in a direct removal of the tramp material without it crossing the path of feed to reducing chamber 34, which would present the danger of its again falling into the reducing chamber 34 under the influence .of the feed from hopper 36.

It is to be noted that each of the teeth 69 and 10' has three operative positions in each of which diflerent edges I'll and different portions .of edges I12 and I13 are in a working position at one time. Therefore, when one set of shearing edges becomes dull from use, teeth 69 and I0 may be removed and rotated 120 or 240 degrees thereby presenting new shredding edges. In addition, the teeth 69 and I0 may be turned over, face'for face, in which case previously trailing edges I12 and I13 become leading edges.

It is therefore evident that the rotor 62 with the hammer teeth I0 and the raking teeth 69 are effective to shred and reduce material in cooperation, first with the edges 53 of teeth 52 of the stationary breaker plate 44 and then with the teeth 55 of bars 54, after which the material is thoroughly shredded and reduced by 'said teeth 39 and III in cooperation with shredding edges 21 I of bars 25, and I24, a final reduction of any material reaching the bar 40 being effected by the cooperation of teeth I0 and edge I40 of said bar 40. The water added by spray pipe 38 will assist the reducing action and wash reduced material through grating 23. As before indicated, teeth 69 operate to maintain the shredding edges 21 of bars 25- exposed to insure a maximum shredding action.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent'of the United States is:

1. A rotor for a shredder comprising a shaft, a plurality of stacked discs keyed to said shaft, at least one of said discs having a wide mouth angular notch formed to receive a tooth in the form of an equilateral triangle while said discs are in stacked relation and contact two sides thereof over an extended area, an equilateral triangularly formed tooth in said notch having a central aperture, and a rod extending through said aperture and through aligned apertures in some of said discs to'hold said tooth in place, said tooth be-' least some of said discs having peripheral notches,

removable teeth in said notchesv having apertures, rods extending through said apertures and through aligned apertures in some of said discs and operating to hold said teeth in place, said rotor also including'a pair of end discs rotatably mounted on said shaft, means for clamping said end discs in place, said end discs having apertures which'align with said tooth holding rods to per.-

mit their removal by' longitudinal movement when said end discs are in one position of adjustment, said end discs being adjustable to another position to maintain said tooth holding rods against longitudinal movement.

, 3. A shredder rotor comprising a shaft, a pair of groups of identical discs keyed on said shaft, each group of discs being formed by identical discs and the discs of the two. groups having substantially equal diameters and having peripheral notches, the discs of one group having notches of greater depth than'those of the other group, and removable teeth having equal heights mounted in said disc notches whereby the tips of the teeth associated with one group of discs will travel in a greater circle than those of the other group.

4. A shredder rotor comprising a shaft, a pair of groups of identical discs keyed on said shaft, each group ofdiscs being formed by identical discs and the discs of the two groups having substantially equal diameters and having peripheral notches, the discs of one group having notches of greater depth than those of the other group, and removable teeth formed as equilateraltriangles of equal heights and mounted in said disc notches whereby the tips of the teeth associated with one group of discs will travel in a greater circle than those of the other group.

5. In a shredder, the combination with a casing having a bottom comprising a tooth grating formed by spaced toothed bars extending longitudinally thereof, of a rotor' mounted in said casing, said rotor having a plurality of removable teeth of unequal thickness, the thicker teeth being positioned to run radially opposite said gratingteeth and the thinner teeth being positioned to run between said grating teeth, said teeth being so spaced that a development ofsaid rotor shows them in transverse aligned rows formed by teeth of the e thickness in each row and each toothspaced transversely from an aligned tooth by a space equal to the width of three teeth, one of like character and two of unlike character.

6. A shredder rotor assembly comprising a shaft, a cylindricalmember on said shaft, adjustable teeth carried on said cylindrical member, rods extending axially through said teeth and cylindrical member, an end plate rotatably adjustable relative to said cylindrical member, said plate having openings through which said rods may slide, said plate being adjustable to hold said rods in place after being insertedthrough said openings.

7. A shredder rotor assembly comprising a rotatable frame member, removable teeth carried by said frame member and projecting radially therefrom, rods extending axially through said teeth and frame member and attaching them together, an end plate rotatably adjustable relative to said frame member, said plate having openings through which said rods may slide axially, said plate being adjustable tohold said rods,

in place against axial movement after being inserted through said openings.

8. A shredder rotor comprising a shaft, a frame mounted on said. shaft, apertured removable teeth carried by said frame, rods extending through said apertured teeth and through aligned apertures in said frame and operating to hold said ,teeth in place, said frame carrying an end disc rotatably mounted thereon, means for clamping said end disc in place, said end disc'having apertures which align with said tooth holding rods to permit their insertion or removal by longitudinal movement when said end disc is in one position of adjustment, said end disc being adjustable. to another position to maintain said tooth holding rods against longitudinal movement. 1 

